If you hear some knocking noise from the front suspension when driving your Infiniti over small bumps, or cracked pavement, most likely it is caused by damaged bushing on compression rod. Some mechanics use different terms for this – tension rod, radius rod, radius arm, radial arm, and so on, but in the official Infiniti Service Manual it is called Compression Rod.
The reason why bushings got damaged: they are defective. They can be damaged after replacement every year if driving in bad road conditions.
What you need is to replace ONLY the bushing, NOT the compression rod itself! Compression rod is pretty expensive part – over $300, bushing is much more cheaper. Moreover, compression rod is not covered under extended (or third-party) warranty because it is just beefy aluminum part, and nothing wrong can happen with it, but bushings are usually covered by extended (third-party) warranty.
Well… This is my story when I had the same problem. However, at that time I did not make any research and just trusted service advisor at Willowdale Nissan Infiniti Service Center.
It happened long time ago in June 2008. I started to hear knocking noise from the front passenger side when driving over rough surfaces, and reported the problem during my oil change visit to Willowdale Nissan Infiniti. Service advisor was Karim Mulji. After inspection he told me that compression rod worn out and had to be replaced. I’ve asked why it is happening? He told that it is because of the way I’m driving – lots of bumps, cracks and stones on the road, and so on. Karim did not even mentioned that there is a known problem with compression rod bushings in Infiniti G35 models of 2003-2006 years – those bushings are defective which causes them to wear out very fast. I figured it out only this year during deep research of what has been done with my car at Infiniti of Willowdale after recent obvious fraud from them which I’ll describe in another post later. What I’ve found is TSB (Technical Servise Bulletin) which exactly describes the problem I saw:
NOISE FROM FRONT COMPRESSION ROD
If you confirm: there is a noise coming from the front compression rod and the bushing is damaged
Actions: replace only the bushing, not the compression rod assy
You may take a look at the TSB in PDF format here:
However, for some reason Infiniti did not apply this TSB for G35 2003 models, only for 2004-2006 models. But there is almost no difference between 2003 and 2004 models, and a lot of Infiniti G35 2003 owners complained on noisy compression rods. I can not believe that certified Infiniti service advisor did not know about this issue.
So, only the bushing was damaged. Compression rod itself is a solid aluminum part! Nothing wrong can happen with it other than in an accident. But Karim decided to replace the whole expensive part rather than bushing. Why? Maybe mechanics at Willowdale Nissan Infiniti are not qualified enough to do the job described in TSB with nice colorful pictures? Bushing replacement is indeed more complex than just entire compression rod replacement.
I’ve also asked if this repair can be claimed under my extended warranty. He looked at the warranty and refused. He also called to the warranty company, but he asked about compression rod, not about the bushing. Recently I’ve figured out that bushings are covered with my FCPP extended warranty Select Plus plan. It is clearly identified:
11. Front and Rear Suspension: …; Bushings; …
Most likely service advisor Karim Mulji decided to choose the easiest and most profitable for the dealership way. If they submit a claim to FCPP warranty, they may get twice less money than when charging the customer for the same repair.
The repair costed me ~$650, however it could be only $56.50 deductible if service advisor could claim it with warranty company.
I’ve tried to escalate the problem to Steve Zehr – Director of Service and Parts Operations Willowdale Nissan Infiniti, but unfortunately he did not want to understand the point at all. He answered through e-mail that compression rod is not covered under FCPP extended warranty, and that TSB about the noise from front compression rod does not apply to 2003 models. But the point was that only bushing was damaged and it is covered by warranty…
This summer I started to hear exactly the same noise from suspension, from the passenger side. In less than two years replaced bushing got damaged again. They are really defective…
During the research I’ve also tried to understand how suspension works and why compression rod bushings can be damaged. These Infiniti G35 Repair Manuals can be helpful if you consider replacement of compression rods by yourself:
Service advisor Karim Mulji also did a big trick on me. He put “Radius Rod” in the invoice (picture above). But there is NO “Radius Rod” in the front suspension – you may check it in the Service Manuals I provided. Radius Rod is the part of rear suspension of Infiniti G35 2003, and it costs approximately $100, not $300.